Mounting structure for removable surfboard fin



June 1970 T. H. MOREY ETAL 3,515,099

MOUNTING STRUCTURE FOR REMOVABLE SURFBOARD FIN Filed June 17, 1968 2Sheets-Sheet 1 1N VENTORS THOMAS H. MOREY BY KARL 0. POPE 11: ROBERT R.T|ERNE Y 7 2a ATTORNES June 23, 1970' T. H. MOREY ETALHOUNTING,$TBUCTURE FOB REMOVABLE SURFBOARD FIN Filed June 17. 1968 2Sheets-Sheet 3 EEEA FIG .5.

- Fl 6 4- INVENTORS THOMAS H. MOREY W a PZOL A TTOR N E Y5 United StatesPatent 3,516,099 MOUNTING STRUCTURE FOR REMOVABLE SURFBOARD FIN ThomasH. Morey, 36 Lincoln Drive; and Karl D. Pope III, 6377 Clemens St., bothof Ventura, Calif. 93003; gngzRobert R. Tierney, 412 Mallory Way, Ojai,Calif.

Filed June 17, 1968, Ser. No. 737,413 Int. Cl. A63c 15/00 U.S. Cl. 9-310Claims ABSTRACT OF THE DISCLOSURE A mounting structure for tightlysecuring a skeg or fin to a surfboard includes a channeled mounting boxbonded in the rearward portion of a surfboard. The sidewalls of the finor skeg base section and sidewalls of the box are shaped withcomplementary tapering. The base of the fin is secured in the box byscrews, which upon tightening, snugly wedge the sidewalls together toprevent wobbling or other relative movement between the fin and box thatcould interfere with surfing operations. The fin and box are formed withrecesses during their fabrication by an injection molding process sothat their walls will be uniformly cooled to thereby avoid shrinkage andwarpage which could cause misalignment between the complementary taperedsidewalls.

The present invention relates to mounting structure for interchangeablymounting multiple surfboard fins one at a time to the surfboard and morespecifically to a mounting box incorporated in a rearward portion of thesurfboard for removably mounting the fins.

BACKGROUND OF THE INVENTION Most conventionally manufactured surfboardshave a skeg or fin molded or otherwise rigidly and permanently fixed tothe rearward undersurface section of the surfboard. Although thistypical type of arrangement is beneficial from the standpoint ofmaintaining the fin perfectly aligned and tightly united with thesurfboard, it consumes excessive space during shipping, and isfrequently cumbersome to handle even by the surfer himself. Also theparticular single design of the permanent fin restricts the range ofmotions and operations that can be performed by the surfer.

Many of these above mentioned drawbacks and limitations were sought tobe overcome by the concept of an easily removable surfboard findescribed in our copending application Ser. No. 628,070 filed Apr. 3,1967, entitled Surfboard With Removable Skeg, now U.S. Pat. No.3,422,471.

In addition to being able to remove surfboard fins for the purpose ofeasy repair and packaging economy surfers often wish to experiment withvarious fin designs but are presently required to use numeroussurfboards each having a particular fin. If quickly demountableinterchangeable fins were available, the surfer could substitutedifferent types of fins for best developing and enhancing skills, couldexperiment with new designs and approaches and could select the optimumfin design to accommodate variable surf and ocean conditions. The surfercould, for example, temporarily prefer a relatively large area deepdraft fin for superior tracking and stability and then substitute forthis, a smaller area more flexible fin for maneuverability andperforming cutbacks.

An especially economical and rapid technique for fabricating surfboardfins is to injection mold them. Previous attempts have produced inferiorresults due in part be cause the mounting structure components arenonuniformly cooled. This results in material shrinkage and excessivestresses that engender warpage and misalignment. The stress bearingsurfaces of the components intended to be snugly interfitted aretherefore mismatched and only a loose coupling can be achieved. Whenthis situation arises there is a concomitant adverse result that thesurfboard wobbels, experiences unpredictable behaviour and becomesdifficult to maneuver.

BRIEF SUMMARY OF THE INVENTION Briefly described the present inventioncontemplates a mounting box for permanent installation within a cavityformed in the rearward undersurface of a surfboard and an injectionmolded skeg or fin dimensioned for being removably mounted within anelongated channel formed in the box. The box has a top wall, a bottomWall arranged in fiush alignment with the surfboard undersurface andspaced sidewalls which taper from the channel opening to the top walllocated at an interior location of the surfboard body.

The fin is integrally formed with a base section having taperedsidewalls shaped so that when the base section is inserted within thechannel, the box and base section can be wedged together to snuglyinterfit and prevent relative motion between the box and fin. Thewedging action of the matched tapered sidewalls prevents relative motionbetween the fin and box that could otherwise interfere with thesurfboard stability and maneuverability.

The base section sidewalls are formed with recessed areas which make theoverall fin more lightweight and promote uniform cooling duringfabrication by the injection molding process so that shrinkage andmisalignment tendencies are minimized. In a similar manner the box mayalso be fabricated by an injection molding technique and incorporate inits sidewalls hollow areas to eliminate shrinkage and misalignment. Thebase section is sized so that when the fin and box are secured togetherby securing means, the base section is maintained in slightly spacedrelationship from the box top wall when the complementary sidewalls arewedged together.

The recessed areas formed in the base section sidewalls may be ofrectangular shape and symmetrically arranged on each sidewall.

In accordance with one construction of the present invention thesecuring means may be characterized by internally threaded socketsmounted at the forward and rearward ends of the box top wall andcorresponding screws insertable through openings in the base section,the screws having flat heads dimensioned to lie in flush alignment withthe base section exterior bottom wall when the screws are fullytightened into their sockets.

BRIEF DESCRIPTION OF THE DRAWINGS The numerous benefits and uniqueaspects of the present invention will be fully understood when thefollow ing detailed description is studied in conjunction with thedrawings, in which:

FIG. 1 is a perspective View of the undersurface of a surfboard showinga fin locked in the mounting box.

FIG. 2 is a perspective, exploded view showing a fin and correspondingmounting box, a cavity formed in the surfboard for receiving themounting box and a flexible peel-away strip used when the mounting boxis 'being installed in the cavity.

FIG. 3 is a longitudinal sectional view showing the fin firmly locked inthe mounting box and FIG. 4 is a fragmentary lateral cross sectionalView taken along line 4--4 of FIG. 3 showing the fin firmly wedged inthe mounting box.

3 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG.1, a surfboard is shown having a skeg or stabilizing fin 11 extendingdownwardly from the surfboard undersurface 12. Pin 11, as shall be fullyexplained, is removably secured within a mounting box 13 constructed toreceive interchangeable fins of various geometrical shapes and sizesthat have identical mounting bases.

Referring now to FIG. 2, fin 11 is integrally formed with an enlargedbase section 14 having fore and aft ends 15 and 16 respectively ofequivalent width. Extending through fore and aft ends 15 and 16 arescrew openings 17 and 18 which intersect the fin center line and liewithin the plane of fin 11. Securing means in the form of a pair offlathead stainless steel socket cap screws 19 and 20 are dimensioned forinsertion into openings 17 and 18 respectively.

Base 14 has a top wall 21 and a bottom wall 22 designed to be in flushalignment with surfboard undersurface 12 when the fin 11 is fullyinstalled for use. Top wall 21 is formed with a fore undercut zone 23and an aft undercut zone 24 to provide necessary clearance for fasteningelements as shall be explained. The sidewalls 25 (only one of which isshown) of base 14 are tapered from bottom wall 22 to top wall 21.Sidewalls 25 are alternately formed with recessed areas 26 and ribs 27.This arrangement of recessed areas 26 and ribs 27 serves to eliminatematerial wastage, make fin 11 lightweight and in addition, promoteuniform cooling of base section 14 when fin 11 is made by an injectionmold process. Uniform cooling greatly minimizes shrinkage andmisalignment tendencies of the fin sidewalls 25 which as shall be fullydescribed must make a tight tapered fit with corresponding sidewalls ofbox 13.

A rectangular shaped flexible peel-away strip 28 is used for assistingthe permanent installment of mounting box 13 into surfboard 10. The Wayin which it is used shall be described.

Mounting box 13 has fore and aft exterior end walls 29 and 30 andexterior sidewalls 31 and 32. Disposed centrally in mounting box 13 isan elongated channel 33 having interior sidewalls 34 (only one of whichis shown) that are tapered so as to complement and match the tapering ofbase sidewalls 25. The exterior bottom surface 35 of box 13 isrectangular shaped and aligned to lie flush with the surfboardundersurface 12. Formed on the inner margin or border of bottom surface35 is a ledge 36 which is of a rectangular size substantially equivalentwith that of peel-away strip 28. The purpose of this shall be described.The exterior dimensions of mounting box 13 are substantially equivalentwith those of cavity 37 which is shaped to receive and permanently mountbox 13.

FIG. 3 shows mounting box 13 securely bonded within surfboard cavity 37and fin 11 tightly locked within mounting box 13. A pair of enlargedsections or bosses 39 and 40 are formed adjacent the fore and aft endsof box top wall 38. Bosses 39 and 40 partially encase and anchor a pairof corresponding socket fasteners 41 and 42 that are internally threadedto threadedly receive screws 19 and 20. Bosses 39 and 40 are formed withpas sages 43 and 44 coaligned with screw openings 17 and 18 respectivelyso that when screws 19 and 20 are fully torqued into position their tipswill not contact adjacent sections of box 13 or surfboard 10.

When fin 11 is tightly interlocked with mounting box 13 base top wall 21is spaced by a slight distance d from mounting box top wall 38. Thepurpose of maintaining spaced distance d is to assure suflicient spacefor the wedging action, as shown in FIG. 4, between fin taperedsidewalls 25 and complementary sidewalls 34 of mounting box 13.

As bolts 19 and 20 are torqued into their fully tightened positionsunder tension which may for example be in the order of 18,000 p.s.i.,complementary tapered sidewalls 25 and 34 are wedged together toaccomplish a tight fit. Because the sidewalls are perfectly matched formutual flush engagement, no clearances or spacing exist between them andtherefore wobbling and other relative movement between fin 11 and box 13is prevented. Interlocking fin 11 and box 13 together to achieve thistight wedge fit may be accomplished by inserting a specially shaped tipof a key (not shown) into correspondingly shaped sockets formed in theflat heads of screws 19 and 20.

As shown in FIG. 4 ribs or partitions 45 and hollow areas 46 arealternately formed between the box tapered sidewalls 34 and exteriorsidewalls 31 and 32. As in the case of fin recessed areas 26 hollowareas 46 serve to minimize material wastage, make the overall mountingbox as lightweight as possible consistent with adequate strength andpromote uniform cooling to assure perfect alignment of tapered sidewalls34.

Referring again to FIG. 2 the mounting box 13 is firmly and permanentlybonded within surfboard cavity 37 so that surfboard 10 and box 13 act asan integral unit. Previous attempts to shape fins and mounting boxes byinjection molding techniques have resulted in imperfect contouring andmisalignment with the adverse result that the sections intended totightly interfit are mismatched. When this situation arises theclearances produce a loose fit that causes wobbling which greatlyimpairs surfboard maneuverability.

Perfect matching alignment between the tapered sidewalls of the mountingbox and fin base is achieved by dimensioning the molds (not shown) to beused in the injection molding process such that the recessed areas andhollow areas are formed in the fin base and mounting box respectively.The recessed and hollow areas are arranged in patterns for causing theplastic material to cool substantially uniformly. As box 13 is beinginjection molded, the socket fasteners 41 and 42 are positioned so as tobe partially encased and anchored within the box in a manner sufficientto prevent water leakage into the surfboard interior during surfing.

When the mounting box is adequatel cooled to its ultimate shape it ispositioned in surfboard cavity 37 and firmly secured to adjacentsurfboard material by any suitable bonding material. Box 13 is orientedwithin cavity 37 so that its bottom surface 35 is flush with surfboardundersurface 12. When the bond has set flexible strip 28, which may beconstructed of polyethylene, is pressed onto ledge 36. Surfboardundersurface 12, box bottom surface 35, and strip 28 are thensimultaneously coated with conventional coating material as many timesas necessary. Leakage of the coating material down mounting box taperedsidewalls 34 and into channel 33 is blocked by strip 28. Strip 28prevents coating material from becoming deposited on tapered sidewalls34 where it could seriously interfere with the desired tight wedge fit.After the necessary additional coating is applied and the sanding andglossing operations are completed the strip 28 is easily peeled awayleaving the mounting box 13 in condition to receive a fin 11.

By way of example the fin 11 may be constructed from polypropylene oracrylonitrile butadiene styrene and the box 13 may be constructed fromany suitable plastic material compatible with the surfboard material andbonding material intended to be used.

OPERATION Keeping the above construction in mind it can be understoodhow many of the previously described disadvantages of prior art mountingstructures for removably mounting a surfboard fin are overcome orsubstantially eliminated by the present invention.

Assuming that the surfer has arrived at a surfing location withsurfboard 10 incorporating mounting box 13 and a plurality of differenttypes of fins 11, he is prepared to realize the benefits of the presentinvention. After selecting one of the fins he merely positions its basesection 14 into box channel 33 and proceeds to torque screws 19 and 20into their respective sockets 41 and 42 until tapered sidewalls 25 and34 accomplish the predetermined optimum snug wedge fit. Afterexperimenting with this first fin the surfer may desire to substitute adifferent type of fin. He then merely untightens screws 19 and 20,removes the first fin and replaces it with a second interchangeable finhaving a base section 14 that is identical with that of the' first finas well as those of subsequent fins that the surfer might also like toexperiment with. i

It can be seen that the surfer may use a set of interchangeable fins toaccommodate his various surfing desires and be assured that the tightwedge fit between the mounting box which is integrally united with thesurfboard and the fin base will assure elimination of wobbling and othertypes of relative motion between mounting box 13 and fin 11 which couldimpair surfing maneuverability. i

From the forgoing it will be evident that the present invention hasprovided mounting structure for a surfboard fin in which all of thevarious advantages are fully realized.

What is claimed is:

1. Structure for removably mounting a surfboard fin comprising:

(a) a mounting box positionable within a cavity in the undersurface of asurfboard, the box having a top wall, a bottom wall aligned flush withthe surfboard undersurface and spaced sidewalls tapering towards the topWall that define an elongated channel;

(b) an injection-molded fin having a base section with tapered sidewallsshaped so that when the base section is inserted within the channel, thebox and base section can be wedged together to snugly interfit andprevent relative motion between the box and fin, said base sidewallshaving recessed areas to make the fin lightweight and promotesubstantially uniform cooling so shrinkage and misalignment tendenciesare minimized; and

(c) securing means for securing the base section and box together, thebase section being sized to be slightly spaced from the box top wallwhen the sidewalls are wedged together.

2. The structure according to claim 1, in which said recessed areas areof rectangular shape symmetrically formed in the base sidewalls.

3. The structure according to claim 1, wherein the box isinjection-molded, the sidewalls thereof incorporating hollow areas, thehollow areas serving to make the box lightweight and promotesubstantially uniform cooling so shrinkage and misalignment tendenciesare minimized.

, 4. The structure according to claim 1, wherein the securing means ischaracterized by first fastening elements mounted at the forward andrearward ends of the box top wall and second fastening elements arrangedto cooperate With corresponding first fastening elements to secure thefin and box together.

5. The structure according to claim 4, wherein the first fasteningelements are internally threaded sockets and the second fastenerelements are screws insertable through openings in the base section, thescrews having flat heads dimensioned to lie in flush alignment with thebase section exterior bottom wall when the screws are fully tightenedinto their sockets.

References Cited UNITED STATES PATENTS 3,137,873 6/1964 Garrolini 9-3103,287,754 11/1966 Price et a1. 9310 3,323,154 6/1967 Lambach 93 103,422,471 1/ 1969 Morey ct a1. 9310 MILTON BUCHLER, Primary Examiner P.E. SAUBERER, Assistant Examiner US. Cl. X.R. 114-126

